Problems of therapy and search for curative options in infantile acute B-cell lymphoblastic leukemia: a clinical case

Infantile acute B-cell lymphoblastic leukemia (B-ALL) is a rare leukemia that develops in children of the first year of life, prone to an aggressive course, a combination of unfavorable prognostic factors, frequent relapses and “switching” of tumor cell differentiation from lymphoid to myeloid. In addition, the physiological features and high vulnerability of the infant's body to the influence of unfavorable external factors cause a high frequency of severe complications of both the underlying disease and the specific treatment, which limits the possibilities of therapy and reduces the likelihood of a favorable outcome in such patients. In this regard, there is no doubt that the search for new curative options that increase the effectiveness and reduce the toxicity of therapy for B-ALL in infants is highly relevant. Given the rarity of this type of leukemia, fundamental studies of the biology of infantile leukemia, extensive clinical trials, and exchange of experience between transplant centers involved in the treatment of such patients are important for improving the effectiveness of its therapy. The clinical case presented in this article demonstrates the main problems of therapy for infantile B-ALL: the initial presence of a set of unfavorable prognostic factors (MLL gene rearrangement, lack of CD10 expression on tumor cells, age under 3 months, hyperleukocytosis, and central nervous system damage at manifestation), “switching” of the blast cell line from lymphoid to myeloid, poor response to glucocorticosteroids and development of severe complications limiting the possibilities of therapy intensification already at the stage of induction therapy, refractory course, relapse at late stages after allogeneic hematopoietic stem cell transplantation. Moreover, an individualized approach and the use of new treatment methods, including immunotherapy, cell therapy and apoptosis inducers, allowed the patient to achieve clinical and hematological remission with negative minimal residual disease a year after allogeneic hematopoietic stem cell transplantation, even after a relapse of leukemia.